Process and apparatus for crimping yarns and the like

ABSTRACT

Process and apparatus for crimping yarns or the like by the action of a heated flowing gaseous medium, the yarns being exposed to the heated flowing gaseous medium in two successive treatment chambers. Yarns of synthetic linear high molecular weight substances can be crimped by means of the process and apparatus according to the invention in a simple way and at high yarn speeds.

United States Patent Schmid et al.

[ Feb. 8, 1972 [54] PROCESS AND APPARATUS FOR CRIMPING YARNS AND THE LIKE [72] Inventors: Hans Schmid, Ludwigshafen; Heinrich Feldhoif, Bad Duerkheim; Wolfgang Martin, Ludwigshafen; Heinz Fessmann, Neumuenster; Edeleried Hahn, Ludwigshafen, all of Germany [73] Assignee: Badische Anilin- & Soda-Fabrik Aktiengesellschatt, Ludwigshafen/Rhein, Germany 22 Filed: Sept. 10, 1969 211 Appl.No.: 856,557

[30] Foreign Application Priority Data Sept. 13, 1968 Germany ..P 17 85 344.0

[56] 1 References Cited UNITED STATES PATENTS 3,268,971 8/1966 Lockwood 3,304,593 2/1967 Burkland ..28/1 .2 3,346,932 10/1967 Cheape ..28/1.4 3,417,445 12/1968 Gemeinhardt et al. 28/7212 3,425,108 2/1969 Cerutti et a1 ..28/l.4 3,484,914 12/1969 Cerutti et a1... 28/7212 2,584,043 1/1952 Oberly 28/72.12 2,586,800 2/1952 Elvin et a1 ..28/1.4 2,622,961 12/1952 Finlayson et al.. .8/149.3 2,664,010 12/ 1953 Emerson ..68/5 2,852,906 9/1958 Breen ..28/72.12 3,259,952 7/1966 Caines ..28/1.4 3,262,181 7/1966 Hawkins et al. ..28/72.1 1 3,282,768 1 H1966 Caines 3,460,359 8/1969 Schiffer ..68/. R

Primary Examiner-jay H. Woo Attorney-Johnston, Root, O'Keeffe, Kcil, Thompson & Shur tlefi" [57] ABSTRACT Process and apparatus for crimping yarns or the like by the action of a heated flowing gaseous medium, the yarns being exposed to the heated flowing gaseous medium in two successive treatment chambers. Yarns of synthetic linear high molecular weight substances can be crimped by means of the process and apparatus according to the invention in a simple way and at high yarn speeds.

12 Claims, 1 Drawing Figure PATENTEU rsa alsrz 3,640,063

FIGS

I NVENTORS.

HANS SCHMID HEINRICH FELDHOFF WOLFGANG MARTIN HEINZ FESSMANN EDELFRIED HAHN 04% w w w ATT'YS PROCESS AND APPARATUS FOR CRIMPING YARNS AND THE LIKE This invention relates to a process and apparatus for the production of crimped yarns or the like by the action of a heated flowing gaseous medium on the said yarns.

Many methods are known for changing the structure of the usually smooth filaments and threads of organic synthetic high molecular weight materials, for example the stuffer box, falsetwist, notch-crimping or edge drawing methods. Methods for crimping filaments or threads by means of turbulent air currents are also known. These methods are however not satisfactory in every respect either because the rate of production is not adequate or because these methods are susceptible to disturbance on account of the moving mechanical elements used.

It is an object of this invention to provide a process for the production of crimped yarns or the like which makes it possible to achieve a high rate of production.

It is anotherobject of the invention to provide a method and apparatus for the production of crimped yarn or the like which are simple and not liable to disturbance.

These and other objects which will be evident from the following description, are achieved by the present invention.

In accordance with this invention a process for the production of crimped yarns from synthetic linear high molecular weight materials by conducting the yarns through two treatment zones connected together, in which the yarns are exposed to the action of a plasticizing flowing gaseous medium having a temperature of at least about 80 C., comprises passing the yarn, in a first treatment zone through which a heated gaseous medium flows, through a small narrow vibrating cylindrical tube secured at one end which is kept vibrating by the flowing gaseous medium and in turn imparts to the flowing gas vibrations having at least the frequency of sound and exposing the yarn in a following second tubular treatment zone vto vibrations of the heated flowing gas formed by coupling the vibrations of the gas flowing from the first treatment zone through the narrow tube to the second treatment The invention also includes apparatus for carrying out the process comprising at least two successive tubular treatment chambers, charged with a flowing gaseous medium, for the yarn to be passed through the same, the first treatment chamber being provided with a yarn inlet orifice, a supply opening for the flowing medium and a yarn guide tube extending from the yarn outlet end of the chamber into the treatment chamber coaxially to the yarn inlet opening, the yarn guide tube being designed as a vibratory system having a distribution of mass which is not symmetrical to the middle axis, said tube extending beyond the yarn outlet end of the first treatment chamber, and bearing at its end projecting from the first treatment chamber a second axially displaceable tubular treatment chamber having a cross section which varies along the length of the chamber.

Yarn or the like according to this invention includes continuous materials such as yarns, bundles of filaments, individual filaments, and tows. The denier of the individual filaments may for example be from 1 to 20. The number of individual filaments in a filament bundle or yarn may be for example from 2 to a few thousand. The filaments in the filament bundles or yarns to be subjected to the crimping treatment may be in a stretched or partly stretched condition. It is also possible to use filaments having a circular or profiled cross section. It may be advantageous for the filament bundle or yarn to have a certain initial twist, for example a twist of up to 30, particularly up to 25, turns per meter. Such an initial twist imparts to the filament bundle or yarn a certain coherence so that it is more easily handled.

Examples of high molecular weight synthetic linear or practically linear thread-forming organic materials for the production of the yarns or the like are conventional high molecular weight polyamides having recurring amide groups in the main chain, linear synthetic high molecular weight polyesters having recurring ester groups in the main chain, filament-forming olefin polymers, and filament-forming polyacrylonitrile or filament-forming acrylonitrile polymers containing mainly acrylonitrile units. Specific examples of high molecular weight compounds are nylon 6, nylon 6,6, nylon 6,10, polyethylene terephthalate, linear polyethylene and isotactic polypropylene having intrinsic viscosities of from 0.8 to 2.8.

A possible method of carrying out the process according to the invention is as follows:

The yarn to be crimped is taken from a wound package and supplied by means of a conventional conveying means at a constant regulatable speed to the first treatment zone in accordance with this invention. At the same time a heated gaseous medium is injected into the first treatment zone and drives the yarn in the first treatment zone through a narrow, thinwalled tube secured at one end and through a subsequent second treatment zone. The heated flowing gas, by flowing into and past the narrow thin-walled tube which is fixed at one end and is advantageously bevelled at the free end, causes the tube to vibrate (like the reed in'a musical instrument) and is thus itself caused to vibrate at a frequency of sound. In the second treatment zone the yarn is exposed to the vibrations of the heated flowing gaseous medium caused by coupling with the vibrations of the gas in the first treatment zone. This coupling is effected by the gaseous medium flowing from the first treatment zone through the narrow tube into the second treatment zone. It is not necessary to have a special vibration exciter in the second zone. The intensity of vibration of the flowing gas, measured at the outlet from the second treatment zone, is clearly greater than the intensity of vibration of the gas measured for the first zone alone after removal of the second treatment zone.

In a preferred embodiment of the process the vibrations of the gaseous medium in the second zone are in resonance with the vibrations of the gaseous medium in the first zone. The resonance point can easily be adjusted by simple variation of the length and shape of the second treatment zone, either by ear or by means of equipment for measuring the intensity of sound vibration.

The frequency of the fundamental vibration of the gas in the two zones is advantageously from 500 to 10,000 c.p.s., particularly from 1,000 to 6,000 c.p.s. Harmonic vibrations occur in both zones; their frequencies may be as high as 20,000 to 24,000 c.p.s. The fundamental vibration depends on the length, shape and type of material of the vibratory tube in the first treatment zone. It can be calculated approximately by means of an equation given by J. P. Den Hartog and G. Mesmer in Mechanische Schwingungen," Berlin 1952, page 175, formula 114, and may easily be determined by simple preliminary experiment.

It may be advantageous to pass the yarn or bundle of filaments to be crimped, which has come from a stretching means, direct over conveying means to the treatment zones according to this invention. It may also be recommendable to clean the yarn or filament bundle for example by passage through a slot filament cleaner prior to crimping.

After the filaments or the like have been introduced into the first treatment zone, they are conveyed through both zones by means of the flowing gaseous medium. Means for drawing off the treatment filaments or the like are not necessary. However, since the yams or the like have a higher temperature when they leave the second treatment zone, it is advantageous to allow them first to cool without applying tension or under slight tension and then to wind them up. Cooling on the bobbin would result in the formation of high stresses in the wound-up yarn. FIG. 6 of the drawing shows an example of suitable cooling means, in which yarn 24 is cooled between a conveying roller 25 and a cooling jacket 26 cooled by a coolant 9. In order to ensure that the yarn is carried along by the rotating conveying roller, the latter is provided with an appropriate surface, for example a velvet covering. The surface of the cooling jacket consists of polished metal. The yarn can then be supplied to a reel unit 10.

Examples of gaseous media suitable for the process according to this invention are nitrogen, carbon dioxide, steam and particularly (for economic reasons) air. It may be advisable to filter the gaseous medium to remove any solid particles. It is surprising that the air does not cause yellowing of the yarn or the like at thetemperatures used which in some cases are quite high.

In order to impart to the yams or the like a permanent crimp it is necessary that they should be in a plastic condition during the treatment by the vibrating gas, naturally without the yarns or the like sticking together. The yarns are rendered plastic by exposing them to the action of a heated gas. The necessary temperatures of the gaseous medium may vary within wide limits. A temperature range of from 80 to 550 C. has proved to be advantageous in the process according to this invention. The necessary temperatures depend on the melting and plasticizing temperatures of the filament-forming material, on the time in which the gaseous medium can act on the yarn or the like, on the temperature to which the yarn or the like may have been preheated, and on the thickness of the yarn or the like. The temperatures of the gaseous medium may be above the melting point or decomposition point of the filament-forming materials, especially when the yarn or the like is passed through the treatment zones at high speed, i.e., with .a short residence time.

If the filament bundle is introduced into the first treatment zone at a fairly low speed, for example 50 to 150 meters per minute, it is advantageous to choose a temperature for the gas which is slightly above the plasticizing range of the high molecular weight material used. This plasticization range is for example from 80 to 90 C. for linear polyethylene, from 80 to 120 C. for polypropylene, from 210 to 240 C. for nylon 6,6, from 165 to 190 C. for nylon 6, from 215 to 255 C. for polyacrylonitrile and from 190 to 230 C. for polyethylene terephthalate. If the filament bundle is introduced into the first treatment zone at a higher speed, higher temperatures of the gaseous media are necessary because of the shorter residence times of the filament bundles in the zone. For filament bundles of nylon 6 having a total denier 4,400 and consisting of 268 individual filaments for example it is recommended that at a filament feed speed of about 800 meters per minute a temperature of from 350 to 430 C. should be used for the gas, and at a filament feed speed of 1,200 meters per minute a temperature of from 470 to 520 C. The upper limit of the temperature of the gaseous medium used is about 550 C. The optimum temperatures for each type of yarn may easily be ascertained by simple preliminary experiment.

To lower the temperature of the gas required for a permanent set of the filament bundle it may be advantageous to preheat the filament bundle. It is often advantageous to introduce into the treatment zones in accordance with this invention, a yarn or filament bundle which has been stretched at from 120 to 160 C. and which is still hot.

Naturally it is also possible to pass the yarn over a conventional heating means such as a heated godet or plate, prior to introduction into the treatment zones according to the invention.

The velocity of the flowing gas is determined essentially by the pressure at which the gas is introduced into the equipment and by the dimensions of the equipment. Inlet pressures of from 3 to 7 atmospheres gauge, particularly from 4 to 6 atmospheres gauge, have proved to be advantageous.

Equipment which is particularly suitable for carrying out the process according to the invention consists of two successive tubular treatment chambers, charged with a flowing gaseous medium, for the yarn to be passed therethrough, the first treatment chamber being provided with a yarn inlet opening, a supply orifice for the flowing gas and a yarn guide tube projecting into the treatment chamber from the yarn outlet end coaxially to the yarn inlet opening, in which in accordance with the invention the yarn guide tube is designed as a vibratory system whose mass is distributed unsymmetrically to the central axis and which extends beyond the yarn outlet end of the first treatment chamber, and bears at its end projecting from the first treatment chamber a second coaxial displacable tubular treatment chamber having a cross section which varies over the length of the chamber. The variations in the cross section may consist for example in abrupt widenings in the cross section or longitudinal slots radially penetrating the wall of the chamber. The unsymmetrical distribution of mass of the gas guide tube may be achieved for example by chamfen'ng the end which projects into the first treatment chamber. The two tubular treatment chambers are preferably disposed coaxially but an arrangement at an angle is also possible for example if the yarn guide tube connecting the two treatment chambers is bent.

An embodiment of apparatus according to the invention is shown diagrammatically in the drawing by way of example and is hereinafter described with reference to the process according to this invention.

FIG. 1 is a longitudinal section through the two successive yarn treatment chambers; 4

FIG. 2 is a view of the second treatment chamber illustrated in FIG. 1 in the direction A; and

FIGS. 3 to 5 are particular embodiments of the second treatment chamber.

Referring to FIG. 1, one embodiment of apparatus in accordance with theinvention consists essentially of two treatment chambers 15 and 16 which are disposed one behind the other and connected together. The first treatment chamber 15 has a cylindrical sleeve 3 closed at one end by a plate 2 and at the other end by a disc 6. The plate 2 is secured to the sleeve 3 by screws 7. A bolt 1 is inserted in the plate 2 and is provided with a yarn inlet orifice 17 coaxial to the axis of the sleeve 3 for feeding the yarn 24 into the first treatment chamber 15. At the end of the bolt 1 which projects into the sleeve 3, the yarn inlet orifice is provided with a conical widening 18. The disc 6 arranged at the other end of the sleeve 3 has firmly secured to it a yarn guide tube 4 which passes through the disc 6, is arranged coaxially to the yarn inlet orifice l7 and projects into the conical widening 18 of the yarn inlet orifice 17. The disc 6 is secured to the sleeve 3 by screws 8. A second treatment chamber 16 is arranged at the end of the yarn guide tube projecting from the treatment chamber 15. According to FIG. I, the second treatment chamber 16 consists of a cylindrical tube 11 which is pushed coaxially onto the yarn guide tube 4 and can be secured thereon by means of a locking screw 12. The tube 11 is provided at the end projecting beyond the yarn guide tube 4 with radial slots 19 passing through the wall of the tube (see also FIG. 2). There may be two slots 19 but the crimping effect increases with the number of slots. From four to 18 slots have proved to be favorable. The width of the slots is advantageously from 0.3 to 1 mm., preferably from 0.4 to 0.6 mm. In order that the length of the slots should be variable, a cylindrical sleeve 13 may be slid over the tube 11 and secured by means of a screw 14. The length of the yarn guide tube 4 projecting from the treatment chamber 15 is advantageously kept short.

The gaseous medium necessary for treatment of the yarn passed through the two chambers 15 and 16 is supplied to chamber 15 through an inlet 5. The diameters of the yarn inlet orifice 17 and of the yarn guide tube 4 are so correlated that the greater part of the gaseous medium passes into the yarn guide tube and drives the yarn supplied through the yarn inlet orifice 17 through the yarn guide tube 4 and the treatment chamber 16. If necessary, a tube arranged coaxially to the yarn inlet orifice 17 may be attached to the bolt 1 on the yarn inlet side, through which the yarn is fed in order to preheat the yarn by means of the portion of the gaseous medium issuing from the yarn inlet orifice. The length of this tube is advantageously of the order of magnitude of the length of the apparatus shown in FIG. 1.

Special embodiments of the second treatment chamber 16 are shown in FIGS. 3 to 5. FIG. 3 shows a tubular treatment chamber having slots 20 passing radially through the wall perpendicular to the axis of the treatment chamber, while in FIG.

4 slots are provided which are inclined to the axis of the chamber. FIG. 5 is a partial longitudinal section of apparatus composed of two treatment chambers and shows a further second tubular treatment chamber 16 slipped on the yarn guide tube 4 and provided with an abrupt widening in the cross section at 22.. The treatment chamber is also provided on the outlet side with a conical widening 23.

To bring the vibrations of the gaseous medium in the second treatment zone into resonance with the vibrations in the first zone, the tube 11 is first slid onto the yarn guide tube 4 without the sleeve 13 until the resonance point is approximately reached. This is generally the case when during sliding of the tube 1 1 onto the yarn guide tube 4 this has its end inside the tube 11 at a distance of a few millimeters from the beginning of the slots 19. By applying the sleeve 13 and varying the length of the slots by displacing the sleeve, fine adjustment of the resonance point can be carried out. When using a treatment chamber 16 according to FIG. 5, the resonance point is reached when the end of the yarn guide tube 4 within the treatment chamber 16 is at a distance of a few millimeters from the first abrupt widening.

The ratio of the internal width of the yarn guide tube 4 to the internal width of the yarn inlet orifice 17 is advantageously from l.4:l to 25:1, preferably from 1.5:1 to 20:1. The dimensions themselves depend on the thickness of the yarn or yarn bundle to be crimped. Generally it is advantageous to choose an internal width which is not greater than is necessary for conveyance of the yarn in order to keep the consumption of gas at a minimum. Thus for a yarn having a total denier of 3,600 the width of the yarn inlet orifice is advantageously 1.2 mm.

The total dimensions of apparatus according to the invention as shown in FIG. 1 are fairly small; they are usually in the decimeter range, advantageously from to 30 centimeters.

Metals or metal alloys, particularly those which are stable to corrosion by oxygen at high temperatures, such as corrosion resistant chromium-nickel-steels or brass, are well suited as materials for the production of apparatus according to the invention.

Metallic materials resistant to oxidation and having high longtime alternating stress strength, even at high temperatures, as for example pure nickel, nickel-chromium alloys or nickel-chromium-iron alloys, if necessary with elements which increase vibration fatigue strength, such as molybdenum, vanadium and others, are well suited for the thin-walled vibratory yarn guide tubes 4.

Yarns treated according to the invention are distinguished by elasticity, great bulkiness and voluminosity. Special disarrangement of the individual filaments in the crimped yarns or filament bundles is not necessary. The individual filaments in the yarn or filament bundle have an undulatory structure with bulges pointing in varying directions, i.e., they may be described as three-dimensional crimped yarns. By reason of the fixed undulatory structure, yarns or the like which have been crimped according to the invention are elastic under tensile stress. The great bulkiness and fullness of the yarns or the like imparts a particularly high covering power and a warm pleasant handle to fabrics prepared from such yarns or the like. When yarns or the like which have been treated according to the invention are processed for example into carpets, the pile of the carpet exhibits an excellent stability. Yarns or the like which have been crimped according to this invention can be dyed much better than untreated yarns or the like.

Yarns which have been crimped in accordance with the invention exhibit a good blooming effect, i.e., they may be almost freed from crimp by a treatment under heat and tension so that they can be easily processed, for example tufted and practically regain their crimp after treatment with hot water, as in dyeing.

The process and apparatus according to the invention are distinguished by great simplicity and are therefore extremely insensitive to disturbances. The small dimensions of the apparatus according to the invention should be emphasized.

Since there are no moving intricate mechanical parts in the process or apparatus according to the invention, defects observable in equipment having moving mechanical parts, particularly at high production rates, do not occur. The vibrating metal tube of the apparatus according to this invention in the first treatment zone can fulfill its function even for long periods without showing fatigue phenomena. Investment and operating costs are low. The speed at which filaments or the like can be crimped is an outstanding advantage. Good crimping results are achieved even with yarn discharge speeds from the second treatment zone of 1,200 meters per minute or more. It is a particular advantage that these high speeds can be maintained over long periods. Since bundles of filaments or yarns having a very large number of individual filaments or a high total denier can be crimped by the process according to this invention, there is obtained, in combination with the high crimping rate, a very high crimping capacity. The process is very economical.

The invention is illustrated by the following examples.

EXAMPLE I A nylon-6 yarn having a total denier of 1,100 which consists of 67 individual filaments and has an initial twist of 6 turns per meter is taken from a wound package and supplied by means of a delivery means at a rate of 800 meters per minute to the crimping equipment shown in FIG. 1. The yarn is passed through the yarn inlet orifice 17 into the treatment chamber 15, through the yarn guide tube 4 and through the treatment chamber 16. The yarn inlet orifice 17 has an internal width of 1.1 mm. and an opening angle B of 30. The yarn guide tube 4 has an internal width of 2.0 mm., an external diameter of 3.0 mm., a length of 59 mm. and a bevel of 30 at its free end in the treatment chamber 15. The yarn guide tube 4 has, on the side facing the treatment chamber 16 after the disc 6, a length of 45 mm., an external diameter of 3.0 mm. and an internal width of 2.0 mm. Air at a temperature of 430 C. and a pressure of 4.75 atmospheres gauge is blown into the treatment chamber 15 through the inlet 5 having a minimum width of 6.5 mm., giving an air consumption of 6.5 m. (STP) per hour. The flowing air conveys the yarn through the yarn guide tube into and through the treatment chamber 16. The air is set in vibration by flowing past the yarn guide tube 4 in the chamber 15. Measurement of the vibration frequency gives a fundamental frequency of about 3,000 c.p.s. The lower limit of air pressure at which vibrations can still be produced is about 3 atmospheres gauge. The cylindrical tube 11 having an external diameter of 10 mm. and a length of 70 mm. and forming the treatment chamber 16 has 16 slots 19 penetrating the periphery of the tube wall and having a length of 45 mm. and a width of 0.5 mm. The point at which the air in the treatment chamber 16 vibrates in resonance with the vibrations in the treatment chamber 15 can easily be found by displacing the tube 11 and varying the length of the slots by means of the sleeve 13; the yarn guide tube 4 then projects by 38 mm. into the tube 11 and the length of the open slots is 30 mm. The entire crimping equipment then has a length of about 180 mm. Measurement of the vibrational frequency gives the value found for the first treatment chamber 15, but with a substantially higher intensity. The yarn passed through the equipment according to FIG. 1 exhibits a particularly good crimp when the vibrations of the air in the chamber 16 are in resonance with those in the chamber 15. The yarn driven out with the air from chamber 16 is crimped so strongly that it can be drawn out to five times its length. The yarn is passed over a cooling drum according to FIG. 6 and then wound up with a tractive force of g.

The crimped yarn has the following properties:

A measure of the texturizing effect is the crimp contraction, i.e., the following value expressed as a percentage. If the crimped filaments are loaded with a weight of 0.002 g. per denier, they extend to a length I. If the filaments are loaded with 0.2 g. per denier, they are extended by the length Lv Crimp contraction is defined as the following value: (L-l )/L 100= percent. The crimp contraction of yarn crimped in accordance with this invention is 19 percent after being kept in water at 60 C. Individual filaments in the yarn have an average of 100 bends per 100 mm. The ultimate tensile strength is 3 .44 g. per denier, the elongation at break is 69 percent. Residual boiling shrinkage is 2.8 percent.

To determine the blooming effect, three measurements of the length of the yarn are carried out:

a. immediately after being taken off the spool,

b. after relaxation of a sample for 24 hours in a standard test atmosphere, and

c. after boiling a sample for minutes in water.

The crimp contraction is calculated by means of the formula (L 0.05-L 0.001 )lL 0.2 100 percent where L 0.05, L 0.001 and L 0.2 denote the lengths of the crimped yarn under the weights of 0.05, 0.001 and 0.2 g. per denier respectively. The values obtained are (a) 4.9 percent, (b) 7.0 percent and (c) 23 percent. Low and comparable values for (a) and (b) and a relatively high value for (c) are characteristic of a good blooming effect.

EXAMPLE 2 A metal tube having an internal width of 1.1 mm. and a length of 150 mm. is applied coaxially in front of the yarn inlet orifice 17 in the equipment described in Example 1. With otherwise the same procedure as in Example 1, the necessary temperature of the air blown in through the inlet 5 is lowered to 330 C.

Yarns of polyethylene terephthalate (PET), polyhexamethylene adipamide (nylon-6,6), polypropylene having a relative viscosity of 2.4 to 2,8 (PP) or a copolymer prepared from 93.5 percent by weight of acrylonitrile, 5.5 percent by weight of methyl acrylate and 1 percent by weight of allylsulfonic acid (PAN) are taken from a wound package and supplied to the crimping apparatus shown in FIG. 1 by means of a feeding device at the speeds given in Table l TABLE 1 Denier]. Air-tem- Length of number of Speed, perature, open slots, Example Material filaments mJmin. C. mm.

The yarns are introduced through the yarn inlet orifice 17 into the treatment chamber 15 and passed through the yarn guide tube 4 into the treatment chamber 16. The yarn inlet opening 17 has an internal width of 1.1 mm. and an opening angle B of 30. The yam guide tube has an internal diameter of 2.0 mm., an external diameter of 3.0 mm., a length of 59 mm. and a bevel of 30 at its free end in the chamber 15. The yarn guide tube 4 has, on the side facing the treatment chamber 16 after the disc 6, a length of 45 mm., an external diameter of 3.0 mm. and an internalwidth of 2.0 mm. Air at the temperatures indicated in Table l and a pressure of 4.75 atmospheres gauge is blown into the treatment chamber 15 through the inlet 5 having a minimum width of 6.5 mm., resulting in an air consumption of 6.5 m. (STP) per hour. The flowing air conveys the yarn through the yarn guide tube into and through the treatment chamber 16. The air is set in vibration by flowing past the yarn guide tube in the chamber 15. Measurement of the vibration frequency gives a fundamental frequency of about 3,000 c.p.s. The lower limit of air pressure at which vibrations can still be produced is about 3 atmospheres gauge. The cylindrical tube 11 having an external diameter of mm. and a length of 70 mm. and forming the treatment chamber 16 has 16 slots 19 penetrating the periphery of the tube wall and having a length of 45 mm. and a width of 0.5 mm. The point at which the air in the treatment chamber 16 vibrates in resonance with the vibrations in the treatment chamber can easily be found by displacing the tube 11 and varying the length of the slots by means of the sleeve 13; the lengths of the open slots are indicated in Table 1. Measurement of the vibrational frequency (when resonance has been achieved) gives the values found for the first treatment chamber 15 alone, but with a substantially higher intensity. The yarn passed through the equipment according to FIG. 1 exhibits a particularly good crimp when the vibrations of the air in the chamber 16 are in resonance with those in the chamber 15. The yarns are passed over a cooling drum according to FIG. 6 and then wound up with a tractive force of 120 g.

After having been kept in water at 60 C. for 1 minute, the yarns exhibit the crimp contraction values indicated in Table 2 below. The ultimate tensile strength, elongation at break, and change in length after boiling in water are also given in Table 2. The crimp contractions (a), (b) and (c) as defined in Example 1 have also been indicated.

TABLE 2 Crimp Ultimate Elonga- Change Crimp contraccontractensile tion at in tion, percent tlon, strength, break, length,

Example percent g. lden. percent percent (a) (b) (c) We claim:

1. A process for the production of crimped yarns or filaments of synthetic linear high molecular weight organic polymers by conducting the yarns or filaments through two treatment zones connected together in which the yarns or filaments are exposed to the action of a heated flowing gaseous medium which comprises conveying the yarns or filaments through a first treatment zone by a heated gaseous medium having a plasticizing temperature of at least about C. in which zone said polymer yarns or filaments and the gaseous medium flow through a narrow vibrating. cylindrical tube secured at one end and which is kept vibrating in reedlike fashion by the flowing gaseous medium, said vibrations of said tube in turn imparting to the flowing gaseous medium vibrations having at least the frequency of sound, and exposing the yarns or filaments in a subsequent second tubular treatment zone to vibrations of the heated flowing gaseous medium resulting from the vibrations of the gaseous medium flowing from the first treatment zone through the narrow tube to the second treatment zone.

2. A process as claimed in claim 1 wherein the yarns are exposed in the second treatment zone to vibrations of the heated flowing gaseous medium which are in resonance with the vibrations of the gaseous medium in the first treatment zone.

3. A process as claimed in claim 1 wherein yarns or filaments of linear synthetic high molecular weight polyamides having recurring amide groups in the main chain, linear synthetic high molecular weight polyesters having recurring ester groups in the main chain, or linear isotactic polypropylene having an intrinsic viscosity of from 0.8 to 2.8 are used.

4. A process as claimed in claim 1 wherein yarns or filaments of nylon-6 or nylon-6,6 are used.

5. A process as claimed in claim 1 wherein yarns or filaments of polyethylene terephthalate are used.

6. Apparatus for the production of crimped yarns or filaments of synthetic linear high molecular weight organic polymers comprising at least two successive tubular treatment chambers, chargeable with a flowing gaseous medium, for the yarn or the like passed through the same, the first treatment chamber being provided with a yarn or filament inlet orifice, a supply opening for the flowing medium and a small diameter yarn or filament guide tube rigidly mounted in the yarn or filament outlet end of the chamber and extending into the treatment chamber coaxially to the yarn or filament inlet opening without additional support, the guide tube being a reedlike vibratory member having a distribution of mass which is not symmetrical to the longitudinal axis, said tube extending beyond the yarn or filament outlet end of the first treatment chamber, and bearing at its end projecting from the first treatment chamber a second axially displaceable tubular treatment chamber having a cross section which varies along the length of the chamber.

7. Apparatus as claimed in claim 6 wherein the second tubular treatment chamber is arranged coaxially to the first tubular treatment chamber.

8. Apparatus as claimed in claim 6 wherein the second tubular treatment chamber is provided with an abrupt widening in the cross section towards the filament outlet end.

9. Apparatus as claimed in claim 6 wherein the second tubular treatment chamber is provided with longitudinal slots penetrating the wall radially.

10. Apparatus as claimed in claim 6 wherein the yarn guide or filament tube is bevelled at its entrant end.

11. Apparatus as claimed in claim 6 wherein the second tubular treatment chamber is provided with circumferential slots penetrating the wall radially.

l2. Yarns or filaments which have been crimped by the process as claimed in claim 1. 

2. A process as claimed in claim 1 wherein the yarns are exposed in the second treatment zone to vibrations of the heated flowing gaseous medium which are in resonance with the vibrations of the gaseous medium in the first treatment zone.
 3. A process as claimed in claim 1 wherein yarns or filaments of linear synthetic high molecular weight polyamides having recurring amide groups in the main chain, linear synthetic high molecular weight polyesters having recurring ester groups in the main chain, or linear isotactic polypropylene having an intrinsic viscosity of from 0.8 to 2.8 are used.
 4. A process as claimed in claim 1 wherein yarns or filaments of nylon-6 or nylon-6,6 are used.
 5. A process as claimed in claim 1 wherein yarns or filaments of polyethylene terephthalate are used.
 6. Apparatus for the production of crimped yarns or filaments of synthetic linear high molecular weight organic polymers comprising at least two successive tubular treatment chambers, chargeable with a flowing gaseous medium, for the yarn or the like passed through the same, the first treatment chamber being provided with a yarn or filament inlet orifice, a supply opening for the flowing medium and a small diameter yarn or filament guide tube rigidly mounted in the yarn or filament outlet end of the chamber and extending into the treatment chamber coaxially to the yarn or filament inlet opening without additional support, the guide tube being a reedlike vibratory member having a distribution of mass which is not symmetrical to the longitudinal axis, said tube extending beyond the yarn or filament outlet end of the first treatment chamber, and bearing at its end projecting from the first treatment chamber a second axially displaceable tubular treatment chamber having a cross section which varies along the length of the chamber.
 7. Apparatus as claimed in claim 6 wherein the second tubular treatment chamber is arranged coaxially to the first tubular treatment chamber.
 8. Apparatus as claimed in claim 6 wherein the second tubular treatment chamber is provided with an abrupt widening in the cross section towards the filament outlet end.
 9. Apparatus as claimed in claim 6 wherein the second tubular treatment chamber is provided with longitudinal slots penetrating the wall radially.
 10. Apparatus as claimed in claim 6 wherein the yarn guide or filament tube is bevelled at its entrant end.
 11. Apparatus as claimed in claim 6 wherein the second tubular treatment chamber is provided with circumferential slots penetrating the wall radially.
 12. Yarns or filaments which have been crimped by the process as claimed in claim
 1. 